<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <link rel="stylesheet" href="css/style.css">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
</head>
<body>
<h1>响应式布局</h1>
<div class="main clearfix">
    <div class="col">左侧内容</div>
    <div class="col">中间内容</div>
    <div class="col">右侧内容</div>
</div>
</body>
</html>